Reset amp hours question

Hi, my mom has a trimetric dealy (tells amp hours, volts, etc.), and a trace engineering dealy (controls the float and bulk charging stuff, I think). Her amp hour readings on the trimetric have gotten more and more out of whack. From what I read on this site, it should automatically reset itself when the batteries become full. I think it's had repeated partial charging which caused the amp hours readings to drift. I'm trying to fully charge it with the generator (not enough sun) and see if that's correct. I just turned the generator off and back on to put in more gas, and the trace engineering thing was on float before, but now it's back on bulk. Any ideas on how long it should take to fully charge it? If it's close to full but not fully full, can I just reset it and at least be back to close to accurate? Thanks.

0

Comments

that meter does need other factors programmed into it such as its efficiency at charging and many people can really only take a good guess at that. this means over time that even the best guess would eventually show the compounding of errors. this also does not account for battery aging or any other influences that could change the battery characteristics.
my advice is start over with the meter by resetting it.

My worry is that, say it's at 90% full, because I can't tell what's full anymore after the numbers have drifted so much. If I reset it, and tell it that that's the new full, will it then allow the batteries to go below 50%, which is supposed to be their current cutoff, I guess. It's supposed to be full at 0 amp hours, and 50% at -750 amp hours (I guess the batteries hold 1500 amp hours total). Lately it seems full is somewhere between -100 and -200, probably closer to -200, and 50% is around -560. Thanks for the quick reply earlier. It's really hard to find people who know about this the stuff. The electrician who set it up isn't totally sure about it all.

Oh, and maybe the Trace thing isn't working right. I ran the generator for a while and then restarted it, as I said earlier. It had switched to float during the first run, and the trimetric which had said maybe 75 amps (not amp hours) had gone to about 20 amps when it switch to float from bulk. When I started the generator after stopping it for a bit, it went back to bulk, and started putting in 75 amps, which slowly climbed into the 90s. Not sure what that means.

That would be a huge battery bank! typically as we desire higher capacity we increase the voltage, by running the batteries in series. If you have a 1500 amp hour battery in the 48 volt range this would represent 4 strings of standard L-16 batteries (8 batteries to a string for 32 batteries)

You might check your specs...

Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol

I think I figured it out. There's something called a charge controller (I think that's what it's called), and it can actually tell you when the batteries are full. A friend told me about it a few hours ago, and when we looked at it it said they were charged (probably had been for a while). So I zeroed the trimetric thing. Not sure what the trimetric thing is, but the trace thing is the inverter, and apparently it doesn't really know exactly what the batteries are doing.

As far as the amp hours, I think the system is 12 volts. The trimetric come up with readings from about 12.5 to 14.45 on the volts setting depending on when you check it. Anyways, it's really cool how you helped answer my questions. I really appreciate it.

If these are Flooded Lead Acid batteries then the best way to see how they are is to use a Hydrometer.
Charge the batteries, when in Absorb mode watch the current come down. When they are "full" then do an EQ. After the EQ you can reset the AH on the Trimetric.

Using the charge controler isnt the best way to see if your batteries are full.